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Today's Topics:
1. Re: Line C - Frequency counter problem (Curt Nixon)
2. Re: Line C - Frequency counter problem (Curt Nixon)
3. Re: Line C - Frequency counter problem (David Assaf)
4. digital read-out (Richard Radke)
----------------------------------------------------------------------
Message: 1
Date: Mon, 10 May 2010 15:10:35 -0400
From: Curt Nixon <[email protected]>
Subject: Re: [Drakelist] Line C - Frequency counter problem
To: [email protected]
Cc: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Oh it works fine on all bands up through 20M. 50-50 on 15 and rarely on
10. I made the total cable length including the Y the same length as a
standard INJ cable and adjusted the trimmers while it was all
connected. I have actually considered putting the preamp at the
connector where the Y starts. with the FET input, the effect on the INJ
signal is so minimal as to be nearly unseen with a scope and FET input
probe. Heizenburg was right! I get the same operational success and
issues with two different 4 lines..the A and B. The series input
blocking cap is a few picoF and forms a voltage divider with the input C
of the FET.
Curt
Garey Barrell wrote:
Curt -
I see I'm still blocked out of Drakelist. I get a 550 reject notice.
Guess I posted too often!
I doubt if the INJ line would even tolerate a "Y" cable and continue
to work in transceive. The preamp will boost the signal to the
counter, but does nothing for the transceive function. Don't forget
that the INJ line is "bidirectional", and has a DC control voltage
traveling over it as well.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
Curt Nixon wrote:
Yes...that is all true..I think that is why the counter input is
subject to RFI also..it is Hi Z so any RF/noise is going to get to
the counter. If the counter sees 30MHz along with the 35.644, it
will not lock and count. It works just fine if one puts it on a sig
gen--even down to fairly low levels. Mine is in its own small
enclosure right on top of the R-4. I made up a special cable that
takes the inj signal from a Y connection at the RX end of the regular
inj cable.
The Jackson Harbor Preamp is a fet input device so it offers a lot of
isolation to the Hi Z INJ line.
I really can't understand why AADE does not tell potential customers
that it will not work as described or is marginal when used on the
twins with INJ lines tied together.
The RO is a nice convenience...not a necessity. What it DOES offer
is repeatability..
Curt
KU8L
From Garey Barrell:
The output of the INJ socket is typically about 1-2V p-p at a
frequency that is 5.645 MHz above the dial frequency. So for a dial
setting of 29.999 MHz, the INJ signal is 35.644 MHz. It is a clean
sine wave so should count fine IF the counter is sensitive enough.
This is a fairly low impedance source, but it is highly sensitive to
capacitive loading. If you have every tried transceiving with the
pair, you've found that the receiver sensitivity is down when the TX
is controlling, and transmitter output is down when the receiver is
controlling, especially if anything but a low capacity cable is
used. So obviously, ANY external load or capacity is going to
overload that signal source.
Apparently the AADE device is designed to be used with the receiver
in a stand-alone situation, NOT when trying to use the pair in
transceive.
Personally, I've never seen the need to have a digital readout when
one kHz is 1/4" wide on the dial, but that's another story.......
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
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------------------------------
Message: 2
Date: Mon, 10 May 2010 16:32:31 -0400
From: Curt Nixon <[email protected]>
Subject: Re: [Drakelist] Line C - Frequency counter problem
To: [email protected]
Cc: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Yes...I wasn't very clear on the amp at the Rx approac. It would still
be on the counter leg of the Y. really an "L"...so the INJ path is
still same as original between R and T but the extra cable capacity
going to the counter is reduced by the 12 to 16 inches of cable I have
now up to the RO box on the top of the Rx.
Its one of those things on my to-do list: characterize the whole system
to try to find a definitive problem and solution...but so many other
things to do !!;)
Yes the sensitivity of the RO is not that great as I recall the signal
just goes to an input pin of an 74HC4046 then to the PIC.
Another thing I wanted to try on the barefoot counter was to reduce the
input blocking caps from .1MFd down to a few pico's. the input is a
series .1, a series 100 Ohm , then another .1M in series.. then the
parallel clipping diodes to ground right after the Res. Seems like the
input capacity can be reduced a lot by making the blocking caps
smaller. Couldn't be a lot worse I think.
Garey Barrell wrote:
Sometimes it works, but mostly not, lately. I used to just reply to
the list, but now I reply to all so at least the person I'm addressing
the reply to gets it. Actually they get it twice if the list happens
to work! :-)
You can't put the amp at the junction of the "Y" because of the DC
control voltage. Unless your FET amp passes DC both ways through it!
The problem is most likely the sensitivity of the counter dropping off
with higher frequency, plus the effect of the cable parallel
capacitive loading.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
------------------------------
Message: 3
Date: Mon, 10 May 2010 15:58:33 -0500
From: David Assaf <[email protected]>
Subject: Re: [Drakelist] Line C - Frequency counter problem
To: "[email protected]" <[email protected]>
Cc: "[email protected]" <[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii; format=flowed; delsp=yes
You might consider the cables connecting the counter. Smaller cables
add lots of capacitance ans as such adds load. I have used the
torrestronics unit and another on both the b and c line twins with no
issues using 58 size coax. Good luck. The read out is certainly a
great addition
Sent from my iPhone
David Assaf, III
On May 10, 2010, at 3:32 PM, Curt Nixon <[email protected]> wrote:
Yes...I wasn't very clear on the amp at the Rx approac. It would
still be on the counter leg of the Y. really an "L"...so the INJ
path is still same as original between R and T but the extra cable
capacity going to the counter is reduced by the 12 to 16 inches of
cable I have now up to the RO box on the top of the Rx.
Its one of those things on my to-do list: characterize the whole
system to try to find a definitive problem and solution...but so
many other things to do !!;)
Yes the sensitivity of the RO is not that great as I recall the
signal just goes to an input pin of an 74HC4046 then to the PIC.
Another thing I wanted to try on the barefoot counter was to reduce
the input blocking caps from .1MFd down to a few pico's. the input
is a series .1, a series 100 Ohm , then another .1M in series.. then
the parallel clipping diodes to ground right after the Res. Seems
like the input capacity can be reduced a lot by making the blocking
caps smaller. Couldn't be a lot worse I think.
Garey Barrell wrote:
Sometimes it works, but mostly not, lately. I used to just reply
to the list, but now I reply to all so at least the person I'm
addressing the reply to gets it. Actually they get it twice if the
list happens to work! :-)
You can't put the amp at the junction of the "Y" because of the DC
control voltage. Unless your FET amp passes DC both ways through it!
The problem is most likely the sensitivity of the counter dropping
off with higher frequency, plus the effect of the cable parallel
capacitive loading.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
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------------------------------
Message: 4
Date: Mon, 10 May 2010 21:00:38 -0500
From: Richard Radke <[email protected]>
Subject: [Drakelist] digital read-out
To: [email protected]
Cc: drakelist <[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
Adrian,
What kind of "Y" connector are you using at the jack on the R4C?
I've found the common 3 inch pig-tail Y adapter loads down the PTO on
10 and 15, giving odd readings.
Try using a compact one piece unit (a tight fit), but should solve
the problem. Also make sure the contacts on the T4XC bandswitch are
clean (be gentle..it doesn't take much). If they're dirty, your
readings will be all over the map. You'll find the preselector
setting on 15 and 10 are pretty critical for accurate operation. If
your not "right on" the last 2 digits won't settle down.
Rick
W9WS
------------------------------
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End of Drakelist Digest, Vol 23, Issue 10
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